Astronomers Detect Largest Cluster Of Red Supergiants

MILKY WAY

Washington DC (SPX) Jan 10, 2006
Astronomers said Monday they have discovered "an extraordinarily massive young stellar cluster" within the Milky Way containing at least 14 red supergiants ďż˝ fast-living, quick dying stars that grow to more than 100 times their normal size before exploding as supernovas.

"It is the richest cluster in the galaxy ďż˝ and even in the local group of galaxies," said team leader Don Figer of the Space Telescope Science Institute in Baltimore. Figer and colleagues presented their findings at the American Astronomical Association's annual meeting.

The cluster is exceptional because so far only 200 red supergiants have been discovered across the entire Milky Way. They are up to 1,000 times the mass of the sun and at least 10 times bigger than red giants.

Generally, Figer explained, stars in the red supergiant phase last only about half a million years. In this cluster, the average distance between the supergiants is only about 5 light-years, and the typical total age of the stars is only about 8 million years.

There is one supernova remnant within the cluster, and given the propensity of red supergiants to explode, the cluster becomes a prime area of interest for supernova watchers. The newly discovered cluster appears to be the source of powerful outbursts of X-rays and gamma rays that have been detected from that part of the galaxy. "We think the cluster is a hotbed of supernova activity," Figer said.

The team used the Spitzer and the Kitt Peak telescopes, plus two other instruments ďż˝ the Two Micron All Sky Survey (2MASS) and the Infrared Multi-object Spectrometer (IMOS) ďż˝ to collect infrared observations of the cluster. Objects within the cluster appear about 1 trillion times brighter in infrared than in visible light.

Based on the findings, Figer said, "there are likely more of these clusters (within the Milky Way) and we hope to find them in the next few years."

STELLAR CHEMISTRY

Spitzer Exposes Hundreds Of New Star Clusters In Dust-Drenched Plane Of Milky Way

Pasadena CA (SPX) Dec 14, 2005
Astronomers have at last found inner light! But they didn't find it through the typical Earthly methods of meditation, exercise and therapy. Instead, the light was discovered inside our Milky Way galaxy after hours of deep self-reflection with NASA's Spitzer Space Telescope.